Earthquakes
on a living, breathing planet
Ironically as I was writing this, we had a 3.4 earthquake here in Berkeley, California. It was fascinating studying plate tectonics during an Environmental Science Class years ago and before I was living in San Francisco where I experienced the great quake of 1989.My interest in the earthquake that shook the eastern U.S. spurred me on to do some research. Earthquake faults are found around the world so what processes shake up the Earth?
We tend to view the Earth quite simplistically as we are going about our business on this living planet hurtling through space. The Earth spins on its axis at about 1,000 miles per hour, and 1,525 feet per second at the equator. We don’t notice it and we don’t spin off. Why don’t we feel it? Go to: https://earthsky.org/earth/why-cant-we-feel-earths-spin/
We get a bit shook up when we experience an earthquake. We think we claim ownership to immovable sections of the Earth, dirt, rock, forests and even ocean territory and mineral deposits. Property titles, zoning ordinances, city, county and state boundaries, arguments over property, water and riparian rights, and etc., however no one really owns the Earth! Now I hope this makes you wonder a bit how our own hubris blinds us to the bigger picture.
Earth's layers are made up of the lithosphere, asthenosphere, lower mantle (also known as mesospheric mantle), outer core and inner core. Then there are more details to the sublayers and actual composition of these layers. In essence, we humans are living on the crust of the Earth. The continental and oceanic crusts sit on a thick layer of solid rock known as the mantle. Rock Solid? Yes in most cases. We are actually on tectonic plates on the upper crust of the lithosphere that are situated on a layer of solid rock that is brittle and malleable. The plates flow on the mantle —almost like a liquid. According to the National Geographic Society this Mantle convection describes the movement of the mantle as it transfers heat from the white-hot core to the brittle lithosphere.. So we are not floating on an ocean of molten rock.
How does Plate Tectonics work:
What Would a Journey to the Earth’s Core Be Like?
During an earthquake, primary (P) and secondary (S) waves spread out through the Earth Columbia University. Special stations situated around the world detect these waves and record their velocities as well as the direction of wave travel and whether they have been refracted (bent). Seismic waves travel faster through dense material like solid rocks and slow down in liquids.
Scientists have drastically improved our understanding of seismic events. Here are eight things to know.
https://www.vox.com/energy-and-environment/2017/9/21/16339522/earthquakes-taiwan-japan-afghanistan-morocco-turkey-syria-explained-science